1. Field of the Invention
The present invention relates to a portable ultrasonic underwater sensor that can adequately function as an ultrasonic transmitter-receiver for communication between divers or between underwater bases.
2. Description of the Background Art
Conventional ultrasonic underwater sensors use (a) an ultrasonic underwater sensor of a thickness vibration mode wherein a face for transmitting and receiving a wave is provided in front of a columnar piezoelectric vibrator, and (b) an ultrasonic underwater sensor of a radial vibration mode wherein a face for transmitting and receiving a wave is provided that externally contacts a columnar piezoelectric vibrator using a center shaft in common.
A further description of the prior art will be discussed in detail later with reference to the drawings.